<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width" />
    <title>菜鸟教程</title>
  </head>
  <body>
    <script type="text/javascript">
      const arr = [1, 2, [3, 4]];
      let a = arr[0];
      let b = arr[1];
      let c = arr[2];
      console.log(a);
      console.log(b);
      console.log(c);

      let [a1, b1, c1] = [1, 2, [3, 4]];
      console.log(a1);
      console.log(b1);
      console.log(c1);
    </script>
  </body>
</html>
